Summary: Mainly I distinctly migration for size . To me it makes me easier to transport the F3 (if it is with a small lens better because I fit in your pocket ) , the D5100 is never comfortable (even without the lens). I have no longer the need to carry an external flash because the flash integrated in the F3 is retractable (you can even lean backwards more than 90 degrees) .
Summary: I bought this to take awesome pics of my almost newborn baby, and I cant wait too ! I've been trying all kinds of modes and combinations with the settings, I've even tried the reverse lens technique and love it. Video not the best same with the auto focus (not that fast), but it's an F3.. SO it's perfect for what I need, if not I can just switch to manual focus BAM problem solved, so no biggie.
Summary: The F3 is great. it does it all, stills, video etc. The image quality is what you would expect from an APS-C size sensor. The kit lens is just fine, super sharp in the middle and great on the edges. The color rendition is excellent and on par with Canon and Nikon. (Sony is no stranger to color, they own the pro video market). It is small and very portable. The bad: The screen is almost useless in daylight.
Summary: I've had this camera for over two months now and after daily use, I would recommend it without hesitation. This camera has a solid build quality and feels great in the hands, it starts up quickly, offers all the features you'd expect from a dslr and takes great, quality photos. Battery life is superb and even though I have a spare battery, I haven't had to use it so far even after a full day of shooting. Several things keep it from getting 5 stars, however.
Summary: I love the great detail I get taking pictures with this Sony. And the high resolution of the rear display is fantastic. My only gripe is that the flash unit doesn't power down very well when taking macro pictures.
Summary: Until now the quality of the photos and the size of the camera fullfil all my expectations. I had some problems with the panoramic shooting, the camera sometimes gets an error for some kind of mechanics problem.